1. Field of the Invention
The present invention is directed to a method of plasma treating a surface of a workpiece in an environment of reactive gas, which surface consists at least substantially of at least one synthetic, organic polymer, for increasing the adherence of lacquer on said surface.
It is further directed to a vacuum treatment apparatus for plasma treating a surface of a workpiece in an environment of reactive gas, which surface consists at least substantially of at least one synthetic, organic polymer, in order to increase the adherence of lacquer, which apparatus includes a vacuum recipient, an electrode arrangement for the generation of a plasma, a generator arrangement for the electrical supply of the electrode arrangement and a gas inlet arrangement.
Finally, the present invention is directed to a lacquered, previously plasma surface treated plastic material article.
2. Description of the Prior Art
An extensive literature exists directed on the surface treatment of workpieces. Reference is made to:
EP-A-349, 749; 0, 120, 307; 0, 129, 199; 0,152, 511; to the PA1 U.S. Pat. Nos. 4,072,769; 4,338,420; 4,445,991; 4,297,187; 4,465,715; 4,584,965; 4,678,644; 4,576,692; 4,595,570; 4,874,453; 4,919,745; to the PA1 Japanese Kokai No. 5 385 782, further to the PA1 DE-A-3,822,482; 3,605,492; 3,408,837; 3,125,786; 3,638,719; 3,463,001; 1,105,149; 3,836,948; and to following papers: PA1 Hall Jr., Journal of Applied Polymer Science, vol. 13, p. 2085 (1969), "Bondability of PP, PE by oxygen plasma treatments", PA1 M. Hudis in Hollahan & Bell, "Techniques and Applications of Plasma Chemistry", Wiley 1974, PA1 Matell et al., Ind. Eng. Chem. Prod. Rev. Vol. 3, (64), p. 300, "Low temperature oxide plasma . . . ", PA1 Schonhorn et al., J. Polymer Science B, 4 203 (1966), "A new technique for preparing low surface energy polymers for adhesive bonding", PA1 Modern Plastics International, vol. 20, No. 10, October 1990, Lausanne-CH, pages 74-79, Peter Maplestone: "Plasma technology progress improve options in surface treatment".
Accordingly, a large variety of methods for a plasma treatment of plastic material surfaces is known for improving wettability, bondability or the adherence of a lacquer thereon, in which differently generated plasmas are applied, such as e.g. pulsed plasmas according to the GB-A-2 105 729, microwave plasmas according to the U.S. Pat. No. 4,595,570. As reactive gases e.g. N2--, O2 gas mixtures are used such as disclosed in the U.S. Pat. No. 4,445,991.